As I write this, Carol and I are in London, having just spent a lovely two week European cruise with my sister and her family--my sister married an Englishman and has been living in England for over 25 years. Carol and I savored the opportunity to spend this extended time, and particularly appreciated getting to know our twin niece and nephew better.

Watching the twins caused me to reflect a bit on the observation that two children growing up in the same household, even when they are twins, inevitably blossom with different personalities. Sometimes-as in the case of my own two children, and in the case of my sister and my brother-the differences are so profound one might think they grew up not just in different families, but on different planets.

Many of us know families where some of the children have followed in their parents' path in terms of careers, values, and lifestyles, but one or more of the others have marched to their own drummer, perhaps even becoming the "black sheep" of the family.

My niece stands 5 feet 10 inches tall at age 11, while her brother is only 5 feet 2 inches. He aspires to be an engineer (though I am not sure that he quite knows what an engineer does yet), while she is quite artistic and is moving more and more in that direction. He speaks rather articulately and directly, while her speech is more animated and a bit diffuse. He still has a bit of child-like quality, while she is just a breath away from entering adolescence. My nephew and my sister get along quite well, but my sister finds herself often at odds with my niece-in part, because my niece reminds my sister of herself at that age.

Likewise, my sister and brother (actually half-siblings-we did not grow up together) are complete opposites. She is fun loving, relatively easy going, generally progressive in thought on social issues, and quite flexible. She also spends money quite easily. In contrast, our brother is extremely conservative and rigid in his lifestyle and viewpoint, has difficulty in social situations, and is extraordinarily frugal.

My own two children are likewise quite different--even their memories and attitudes about their childhood are radically different-one recalling a rather content childhood, and the other still processing some old anger. So what is this phenomenon, and what is a parent to do with it!

The debate over nature versus nurture is an old one. There are certain characteristics that seem relatively fixed at birth-some are rather clear, for example a tendency toward introversion or extroversion, while others show up as a tendency toward one end of a continuum or another. Although we as parents may strive valiantly to treat our children equally, it is nearly impossible to do so. First, each will have a different experience growing up-one is always the eldest and others stand in different birth order (twins being the exception).

Second, inevitably, one child will have characteristics that push our buttons more than another-reminding ourselves of our experience growing up or maybe of one parent or the other. For example, during our travels my sister mentioned that she is constantly nagging our niece about keeping her face clean. "Why?" I asked. My sister thought a moment, and then as tears flowed she said "Because I had a face patchy with acne as a kid." A quiet but profound discovery of the link between her own past and her interaction with her daughter.

So, how do we deal with our children's differences? First, recognize that they are each unique individuals, and part of their life journey as children, particularly as adolescents, will be to discover and claim their individuality. Celebrate their differences. Find ways to affirm each of them for the unique talents and strengths. And never, never compare them with one another-at least not aloud.

Second, when you find certain behaviors or actions driving you crazy, or find yourself in constant conflict, pause for a moment and ask why you are making a particular rule, or enforcing particular behavior. Is it for the child's good, or does your motivation really lie in ancient hurts of your own? You may or may not still choose to continue the rule or the behavior, but you will know why. And if, as in my sister's case, it comes out of an earnest desire to spare your child some hurt you experienced, tell the child. Share your honest feelings, so that he or she will hear your "nagging" as an act of love, and not as another note of parental control against which the child may want to rebel.

In short, affirm them often for the uniqueness, for their individuality. Love them for who they are not simply for what they do. Share feelings with them. And listen, really listen to their thoughts and feelings. The rewards will be priceless.